The present invention relates to satellite communications systems. In particular, the present invention relates to downlink beam power gating techniques particularly adapted to variable hop cycle beam laydowns.
Satellites have long been used to provide communication capabilities on a global scale. Typically, a satellite includes multiple uplink and downlink antennas, each of which provides communication bandwidth to a large service region using multiple spot beams. The area covered by a spot beam is commonly referred to as a cell, and color coded spot beams are assigned in a pattern called a laydown to cover the cells that make up a service region.
Spot beams are distinguished from one another by such characteristics as frequency or polarization. These characteristics allowed the spot beams in an appropriately designed laydown to operate without substantial cross channel, co-channel, or cross polarization interference. Each spot beam typically provides a fixed amount of bandwidth. Thus, prior laydowns often operated under the constraint that each cell had the same bandwidth allotment as any other cell. To provide additional bandwidth to a cell therefore meant providing additional spot beams for the cell, a potentially costly and complex proposition.
On the other hand, a laydown may include cells that simply do not need the bandwidth provided by an entire spot beam. However, prior satellites were incapable of reallocating spot beams to meet bandwidth demand, particularly on a dynamic basis. Thus, a risk exists that, after satellite launch, an increase in bandwidth demand cannot be met, and that a decrease in bandwidth demand will result in wasted power.
A need has long existed in the industry for a beam laydown that addresses the problems noted above and others previously experienced.